Method for manufacturing optical member and method for manufacturing semiconductor laser device

ABSTRACT

A method for manufacturing an optical member includes providing a silicon substrate having a first main surface of a {110} plane, forming a mask pattern having an opening extending in a &lt;100&gt; direction on the first main surface of the silicon substrate, and forming a sloped surface of a {100} plane in the silicon substrate by wet etching the silicon substrate from a first main surface side using the mask pattern as a mask. A method for manufacturing a semiconductor laser device includes fixing the optical member formed by the method for manufacturing the optical member and a semiconductor laser element to a mounting board so that laser light emitted from the semiconductor laser element is irradiated to a reflective film of the optical member.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No.2015-149210 filed on Jul. 29,2015. The entire disclosure of JapanesePatent Application No. 2015-149210 is hereby incorporated herein byreference.

BACKGROUND

1. Technical Field

The present disclosure relates to a method for manufacturing an opticalmember, a method for manufacturing a semiconductor laser device, and asemiconductor laser device.

2. Description of Related Art

In the field of optics, and especially for semiconductor lasers, therehas been a need in recent years for smaller packages and higher output.Accordingly, a semiconductor laser device is proposed in which one ormore laser elements and optical members corresponding to the laserelements, such as an optical member having a 45-degree sloped surface,are disposed in a single package, and laser light that is reflectedperpendicularly on the sloped surface is collimated and used. Also, amethod for manufacturing an optical member having a 45-degree slopedsurface in which silicon is used and is subjected to wet etching, inorder to provide an optical member having a 45-degree sloped surface ata low cost (for example, JP2000-77382A, JP2006-86492A, andJP2009-526390A).

However, it may not be easy to make a 45-degree sloped surface bothsmooth and precise in its angle. Also, a simple method for making such amirror has not been established yet, and there has been a need for asimple method of highly precisely manufacturing an optical memberincluding a sloped surface having high smoothness.

SUMMARY

It is an object thereof to provide a simple method for preciselymanufacturing an optical member including a sloped surface having highflatness, as well as a semiconductor laser device including thishigh-precision optical member.

A method for manufacturing an optical member of the present disclosureincludes providing a silicon substrate having a first main surface of a{110} plane, forming a mask pattern having an opening extending in a<100> direction on the first main surface of the silicon substrate, andforming a sloped surface of a {100} plane in the silicon substrate bywet-etching the silicon substrate from the first main surface side usingthe mask pattern as a mask.

Further, a method for manufacturing a semiconductor laser device of thepresent disclosure includes fixing the optical member described aboveand a semiconductor laser element to a mounting board so that laserlight emitted from the semiconductor laser element is irradiated to areflective film of the optical member.

Still fluffier, a semiconductor laser device of the present disclosureincludes a mounting board, a semiconductor laser element disposed on themounting board, and an optical member that is composed of silicon havinga {110} plane and a {100} plane, in which either the {110} plane or the{100} plane is fixed on the mounting board and the other one is coveredby a reflective film, and which reflects laser light emitted from thesemiconductor laser element.

According to one embodiment of the present disclosure, an optical memberincluding a sloped surface with high flatness can be simply andprecisely manufactured, and a semiconductor laser device including thishigh-precision optical member can be provided.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A and 1B are a schematic plan view and a schematiccross-sectional view, respectively, illustrating an embodiment of a maskpattern on a silicon substrate in the present disclosure;

FIGS. 2A to 2F are schematic cross-sectional views illustrating anembodiment of the method for manufacturing an optical member in thepresent disclosure;

FIGS. 3A and 3B are schematic cross-sectional views illustrating anembodiment of the method for manufacturing an optical member in thepresent disclosure;

FIGS. 4A and 4B are a schematic plan view and a schematiccross-sectional view taken along the a-a′ line of FIG. 4A, respectively,showing an embodiment of the semiconductor laser device of the presentdisclosure;

FIG. 5 is schematic cross-sectional view illustrating another embodimentof the semiconductor laser device of the present disclosure;

FIG. 6 is schematic cross-sectional view of another embodiment of thesemiconductor laser device of the present disclosure;

FIG. 7 is schematic cross-sectional view of another embodiment of thesemiconductor laser device of the present disclosure; and

FIGS. 8A, 8B and 8C are a plan view, a vertical side view, and a lateralside view, respectively, illustrating surfaces of the silicon substrateobtained by the method for manufacturing a semiconductor laser device inthe present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

In the description below, embodiments of the present invention will bedescribed appropriately referring to drawings. However, an illustrationdescribed below are intended as illustrative to give a concrete form totechnical ideas of the present invention, and unless otherwisespecified, the scope of the present invention is not limited todescriptions below. Also, description in one embodiment and in oneexample can be applied in other embodiments and examples. The sizes orpositional relationships of members illustrated in each drawing may beexaggerated so as to clarify the description.

Embodiment 1: Method for Manufacturing Optical Member

The method for manufacturing the optical member of the presentembodiment includes

-   -   (a) providing a silicon substrate having a first main surface of        a {110} plane,    -   (b) forming a mask pattern having an opening that extend in a        <100> direction on the first main surface of the silicon        substrate, and    -   (c) forming a sloped surface having the {100} plane by wet        etching the silicon substrate from the first main surface side        using the mask pattern as a mask.

The method described above, may further includes

-   -   (d) forming a reflective film on one side of the silicon        substrate, or    -   (e) dividing the silicon substrate.

a: Provision of Silicon Substrate

A silicon substrate having a first main surface of a {110} plane isprovided. The term “{110} plane” here refers to {110} plane of thecrystal lattice planes in a diamond structure of silicon, which is acrystal structure that is stable under normal temperature and normalpressure, and to crystal planes equivalent to {110} plane. The term“crystal planes equivalent to” means the family of equivalent crystalplanes or facets defined by the Miller index. The first main surface ofthe silicon substrate may have an off angle of about ±2 degrees withrespect to the {110} plane. The off angle is preferably ±1 degree, andmore preferably ±0.2 degree.

The size and the thickness of the silicon substrate can be suitablyadjusted in accordance with the application of the optical member to beobtained and so forth. It is preferable to obtain a plurality of opticalmembers from a single silicon substrate, and accordingly, the siliconsubstrate may have a length and/or width of from a few centimeters to afew dozen centimeters.

The thickness of the silicon substrate is preferably uniform, but thesilicon substrate may include portions of different thickness locally.It is also preferable that the first main surface of the siliconsubstrate and the second main surface on the opposite side arerespectively a surface of the {110} plane. That is, the siliconsubstrate preferably has a second main surface that is parallel to thefirst main surface. The thickness of the silicon substrate can be in arange of 100 μm to a few thousand microns, for example, and can be in arange of 500 to 2000 μm, for instance.

b: Formation of Mask Pattern

A mask pattern is formed on the first main surface of the siliconsubstrate. This mask pattern includes openings, for example, extendingin a <100> direction as shown in FIG. 1. The openings that extend in the<100> direction can be openings that extend in a direction parallel tothe first main surface.

The term “the <100> direction” here refers to a direction perpendicularto (100) plane, which is one of the crystal lattice planes in a diamondstructure of a silicon, which is a crystal structure that is stable atnormal temperature and pressure, and all directions that areperpendicular to crystal planes equivalent to the (100) plane.

The openings in the mask pattern may be openings each having a stripeshape extending in the <100> direction. Also, the openings extending inthe <100> direction may link to openings extending in a directionperpendicular to the <100> direction (namely, in a <110> direction) toform a lattice pattern. For example, the openings extending in the <100>direction may link to openings extending in the <110> direction to forma lattice pattern. The openings extending in the <100> direction hasouter edges (both sides) that are preferably parallel to the <100>direction. Also, the openings extending in the <110> direction has outeredges (both sides) that are preferably parallel to the <110> direction.

The length of the openings extending in the <100> direction can besuitably selected according to the size of the silicon substrate to beused. The width of the openings extending in the <100> direction can besuitably selected according to the height of the sloped surface to beobtained in a subsequent step, etc. For example, the width can be in arange of about 200 to 1000 μm. In the case of including an openingextending in a direction other than the <100> direction, a width of theopening may be the same as or different from the width of the openingsextending in the <100> direction. The sloped surface formed by suchopening extending in a direction other than the <100> direction is notrelated to function as an optical member. Thus, the width of openingsextending in a direction other than the <100> direction is preferablyless than the width of openings extending in the <100> direction. Thisallows the surface area of the silicon substrate to be used moreefficiently. Also, the width of the openings may be fairly large in thecase of being used for division grooves, and can be about 50 to 500 μm,for example.

The depth of the openings corresponds to the thickness of the maskpattern, and for example, is in a range about 0.1 to 1 μm.

The mask pattern can generally be formed using a material that is knownin this field such as a resist film, an insulating film (an oxide filmof silicon, hafnium, zirconium, aluminum, titanium, lanthanum, or thelike) and by a known method such as photolithography and an etchingstep. It is particularly preferable to appropriately select the materialof the mask pattern according to the type of etchant used in wet etching(discussed below).

In the case where the openings that extend perpendicular to the <100>direction, which are described above, are not formed in the mask patternon the first main surface of the silicon substrate, a mask pattern andopenings that extend perpendicular to the <100> direction may be formedon the second main surface of the silicon substrate.

c: Formation of Sloped Surface

The silicone substrate is wet-etched from the first main surface sidethereof using the mask pattern as a mask, so that the sloped surfacehaving a {100} plane is formed. The sloped surface preferably extends inthe <100> direction and has an inclination angle of 45 degrees withrespect to the second main surface (that is, the {110} plane) of thesilicon substrate. In other words, the sloped surface preferably formsan angle of 135 degrees with respect to the first main surface of thesilicon substrate is. The “(100) plane” referred to above may have anoff angle of about ±2 degrees with respect to the {100} plane, and thusmay be a plane having an inclination angle of about 45±2 degrees withrespect to the second main surface. The off angle is preferably ±1degree, and more preferably ±0.2 degree.

The etching described above is preferably be a wet etching, but may beany etching method that allows for anisotropic etching.

The wet etching may be performed using the above-described mask patternas the mask under any conditions, so long as the etchant allows foranisotropic etching. Examples of the etchant include tetramethylammoniumhydroxide (TMAH), potassium hydroxide, sodium hydroxide, ethylenediamine pyrocatechol (EDP), hydrazine, a mixture in which isopropanol isadded to these, or a mixture of these. The concentration of the etchantcan be suitably selected considering the etching rate of the siliconsubstrate or the like. Among materials described above, TMAH ispreferably used for the etchant. This is because TMAH has higheranisotropy in the etching of the {110} plane of silicon substrate thanother anisotropic etchants, and allows for precisely forming a slopedsurface that is inclined by approximately 45 degrees from the mainsurface in the {110} plane of the silicon substrate. TTMAH is preferablyused also because it is easy to handle.

The etching conditions may be such that, in the case where the etchantis TMAH, for example, the etchant temperature is set to be in a range ofabout 80 to 110° C., and the material is immersed for about 2 to 10hours. The immersion time may be adjusted so as to achieve the desiredamount of etching.

In the case where openings that extend in a direction perpendicular tothe <100> direction, which are described above, are also formed in themask pattern used in the description above, a surface is formed (see 11d in FIGS. 8A to 8C) having an inclination angle of about 35 degrees,which is the {111} plane, from a side extending in the <110> direction.This angle may also have an off angle of about ±2 degrees with respectto the {110} plane.

After forming the above-described sloped surfaces of 45 and 35 degrees,the etching is continued, which can form a groove with a cross sectionalshape that is trapezoidal defined by the sloped surfaces extending fromopposing sides in plan view, and when the etching proceeds further, thegroove becomes V-shaped. Since silicon substrates cannot be cleaved ineither the <100> direction or the <110> direction, in the case offorming a trapezoidal or preferably V-shaped groove, the etching ispreferably continued until a V-shaped groove is formed, which allows forperforming the division described below easily at the bottom of the Vshape.

The sloped surfaces are preferably formed to a depth in a range of abouta few hundred microns to a thousand and a few hundred microns, andespecially in a range of about 200 to 1000 μm, from the first mainsurface of the silicon substrate.

d, d′: Formation of Reflective Film

A reflective film may be formed on one side of the silicon substrate.The “one side” here can be appropriately selected according to a form ofusing the obtained silicon substrate. For example, a reflective film ispreferably formed on either the obtained sloped surfaces or the secondmain surface. In the case where the reflective film is formed on theobtained sloped surfaces, the film will be formed at the angle at whichthe surface is inclined, which may lead to difficulty in controlling thefilm thickness, so that the quality of the film may be deteriorated. Forthis reason, it is particularly preferable to form the film on thesecond main surface.

The reflective film can be made of a material capable of reflecting atleast 50% of light emitted from a semiconductor laser element, forexample. In other words, the reflective film can have a reflectivity ofat least 50% with respect to light having the oscillation wavelength ofthe semiconductor laser element. In the case of combining the reflectivefilm with a high-output semiconductor laser element (for, example, asemiconductor laser element having an optical output of at least 1 W),the film is preferably made of a material capable of reflecting at least80%, at least 90% or at least 95% of light having the oscillationwavelength. Example of the reflective film include a single-layer ormultilayer structure film of a metal such as gold, silver, copper, iron,nickel, chromium, aluminum, titanium, tantalum, tungsten, cobalt,ruthenium, tin, zinc, or an alloy of these (e.g., for an Al alloy, analloy of Al and Cu, Ag, or a platinum group metal such as Pt may beused). When the reflective film is made of a metal, a single-layer filmof a metal such as aluminum, gold, silver, or chromium is preferable.

The reflective film may be a dielectric multilayered film or the like inwhich two or more kinds of dielectrics are laminated. This dielectricmultilayered film is preferably a DBR (distributed Bragg reflector)film. Examples of the dielectrics forming the DBR film include an oxidefilm or a nitride film of at least one element selected from the groupconsisting of silicon, titanium, zinc, niobium, tantalum and aluminum.Among them, a layered structure of the oxide of silicon, zinc, niobium,tantalum or aluminum. Further, a first layer of the reflective filmpreferably has good adhesion to the silicon, and for example,Si-containing layer such as SiO₂ is considered to be suitable to serveas the first layer. By adjusting the material and thickness of thevarious layers of the dielectric multilayer film, the dielectricmultilayered film can have a desired reflectivity.

It is particularly preferable for the reflective film to be formed by adielectric multilayer film. Using the dielectric multilayer film canincrease the reflectivity with respect to the oscillation wavelength ofthe laser, as compared to a reflective film formed of a metal. Morespecifically, the reflectivity can be close to 100%. With thisarrangement, an optical member with less light absorption, that is, lessheat generation can be realized. Accordingly, a semiconductor laserdevice with high output can be obtained. The reflectivity of thedielectric multilayered film changes in accordance with the change inthe thickness of each layer of the dielectric multilayered film, so thatit is preferable to form the film perpendicular to a surface on whichthe film is to be formed in a wafer state so that the film having athickness that is the same as the designed value can be obtained.Therefore, it is more preferable that the dielectric multilayer film isformed on the second main surface (the {110} plane) of the siliconsubstrate.

The thickness of the reflective film may be in a range of about a fewtenth micrometer to about a few dozen micrometer, for example,preferably in a range of about 0.1 to 10 micrometer, and more preferably0.3 to 7 micrometer.

The reflective film can be formed by a method known in this art such asa vacuum deposition method, ion plating method, ion vapor deposition(IVD) method, sputtering method, ECR sputtering method, plasmadeposition method, chemical vapor deposition (CVD) method, ECR-CVDmethod, ECR-plasma CVD method, electron beam evaporation (EB) method, anatomic layer deposition (ALD) method. In any method of forming thereflective film, the formation of the film is performed perpendicularlyto the surface on which the film is to be formed.

As described above, forming the reflective film after forming theabove-described sloped surfaces allows for forming the reflective filmhaving good angle precision, high smoothness, or the like, and good filmquality. Accordingly, the reflection efficiency and durability of theoptical member can be enhanced. Also, the optical member can bemanufactured efficiently, easily, simply, and at high precision.Furthermore, the manufacturing cost of the optical member itself can bereduced.

e: Division of Silicon Substrate

The silicon substrate may be divided appropriately. This division may beperformed before or after the formation of the above-describedreflective film.

The division of the silicon substrate is preferably performed in adirection along a 45-degree sloped surface, for example, that is, in the<100> direction. As described above, in the case of forming slopedsurfaces on the silicon substrate, a groove with trapezoidal or V-shapedcross section is formed defined by one or two sloped surfaces, so thatthe division is preferably carried out inside the trapezoidal orV-shaped groove along the direction of the groove. Consequently, in thecase where the mask pattern includes a plurality of openings, two slopedsurfaces can be formed on both sides of a single optical member.

Also, in the case where the {110} plane (first main surface) of thesilicon substrate is present between two sloped surfaces, the substratemay be further divided in a direction parallel to the directionextending in the <100> direction, in the {110} plane of the siliconsubstrate. This division can form a single optical member having justone sloped surface.

Regardless of whether or not etching is performed in the above-describeddirection extending in the <100> direction, it is preferable to performdivision also in a direction perpendicular to the direction along thesloped surfaces, that is, the <110> direction. For this division, agroove defined by slopes formed by etching in a direction extending inthe <100> direction may be used, or an auxiliary division groove orcrack described below may be used.

At the time of dividing the silicon substrate, it is preferable to forman auxiliary division groove and/or crack and perform division. Thisauxiliary groove and/or crack can be formed, for example, by knownmethods such as blade dicing or laser dicing. Among these, it ispreferable to use laser dicing that allows for internal processing of amaterial. With this method, cracks can be formed over approximately theentire surface, no matter how thick the material is, and generation ofdebris during division can be reduced. In the case of using laser dicingthat allows internal processing, an internal-processing laser is emittedby, for example, the laser dicing device to form cracks directly underthe V-shaped grooves, and then, as shown in FIG. 2D, the siliconsubstrate 11 is divided with a breaking device from the lower ends ofthe V-shaped grooves, which serve as the starting point of the breaking.

The size of the silicon substrate after division can be selectedappropriately. For example, a side of the silicon substrate in the <110>direction can be 2.0 mm, and a side in the <100> direction can be 1.0mm.

Embodiment 2: Semiconductor Laser Device

As shown in FIGS. 4A and 4B, for example, the semiconductor laser devicein this embodiment includes:

a mounting board 1;

a semiconductor laser element 4; and

an optical member 5 that is made of silicon having the {110} plane andthe {100} plane, in which one of the {110} plane or the {100} plane isfixed on the mounting board and the other one is covered by a reflectivefilm to reflect laser light emitted from the semiconductor laser element4.

Optical Member 5

The optical member 5 is a member for reflecting laser light emitted fromthe semiconductor laser element 4 to an intended direction. The opticalmember 5 is preferably made of silicon (Si). Silicon has better thermalconductivity than a conventional optical member made of quartz (aso-called prism), so that it is particularly advantageous for use inhigh-output lasers in which the output of the semiconductor laserelement is 1 W or higher.

The optical member preferably has surfaces of the {110} plane and the{100} plane of silicon. That is, a reflecting surface of the opticalmember 5 to reflect laser is preferably one of the {110} plane and the{100} plane. In the present specification, the {110} plane and the {100}plane allows inclination due to an off angle of about ±2 degrees. It ispreferable that one of the {110} plane and the {100} plane of silicon isfixed on the mounting board, and the other is covered by a reflectivefilm. For example, the {110} plane can be fixed on the mounting board,and the {100} plane can be covered by a reflective film and used as thereflecting surface to reflect laser light. The “{100} plane” referred tohere indicates a plane that is at a 45-degree angle with respect to the{110} plane.

This the {110} plane preferably corresponds to the second main surfaceof the silicon substrate in the above-mentioned method for manufacturingan optical member, for example, while the {100} plane is preferably asloped surface formed by etching using a mask pattern having openingsthat extend in the <100> direction.

Generally, the optical member 5 in which the {110} plane or the {100}plane that serves as the reflecting surface is covered with a reflectivefilm as described above is used.

The optical member 5 is disposed opposing the semiconductor laserelement 4. The “disposed opposing” in this case means that laser lightemitted from the semiconductor laser element 4 is irradiated to thereflecting surface of the optical member 5 (that is, the surface coveredwith the reflective film), and the optical member 5 is disposed at aposition where the reflecting surface can reflect this laser light so asto face the semiconductor laser element 4. For example, the reflectingsurface of the optical member is disposed so as to be inclined withrespect to an end portion of the semiconductor laser element on anoptical member side. This reflecting surface reflects laser light, whichallows the optical axis of the laser light emitted from thesemiconductor laser element 4 to be changed to another direction. In thecase where laser light from the semiconductor laser element is emittedparallel to a main surface of the mounting board, then light from thesemiconductor laser element 4 can be emitted perpendicularly to themounting board 1 by selecting the angle formed by the sloped surface andthe main surface of the mounting board to be 45 degrees ±2 degrees, andpreferably 45 degrees ±1 degree, and more preferably 45 degrees ±0.2degree.

There are no particular restrictions on the shape of the optical member5, as long as the optical member 5 includes the above-describedreflecting surface, and any of various shapes can be employed. Forexample, the shape of the optical member 5 may be a polygonal column, apolygonal truncated pyramid, or a combination of these shapes. Theoptical member 5 may further have a sloped surface inclined with respectto the {110} plane (see 11 d in FIGS. 8A to 8C). The inclination angleof the {110} plane of the sloped surface is less than the inclinationangle of the {100} plane with respect to the {110} plane, and forexample, is about 35 degrees.

The reflecting surface of the optical member 5 is disposed preferablywithin about 10 to 150 μm from the semiconductor laser element, and morepreferably within about 20 to 100 μm.

A single optical member 5 may be disposed on the mounting board, or aplurality of optical member 5 may be disposed on the mounting board. Inthe case of disposing the plurality of optical member 5, they arepreferably disposed in a matrix, for example. Also, one optical member 5may be disposed for each semiconductor laser element, or one opticalmember 5 may be disposed for a plurality of semiconductor laserelements.

The optical member 5 is generally disposed on the mounting board 1 via ametal layer and/or an adhesive member. The metal layer may be disposedin an area that is smaller than an area of the surface of the opticalmember 5 that is fixed to the mounting board 1 and/or a planar area ofthe optical member 5, or may be disposed in a planar area equal to theplanar area of these. Also, it may be disposed extending out from theedges of the surface of the optical member 5 that is fixed to themounting board 1. This can ensure a path of heat dissipation from theoptical member 5.

The metal layer may be formed of a single layer of metal such as gold,silver, or aluminum, or is a layered structure including these metals.More specifically, examples of the metal layer include a layeredstructure such as Ti/Pt/Au, Ni/Au, Ni/Pd/Au or Ni/Pd/Au/Pd. In the casewhere the outermost surface of the metal layer is gold, all or a portionof the gold may diffuse into the adhesive member (discussed below) suchas a gold-based solder. In this case, the diffused gold functions as anadhesive member. The metal layer can be formed by any method known inthis field, such as vapor deposition method, sputtering method, orplating method. Among these, forming by sputtering is particularlypreferable.

Examples of the adhesive member include an adhesive member made of ametal material such as Au-based solder material (e.g., AuSn-basedsolder, AuGe-based solder, AuSi-based solder, AuNi-based solder, AuPdNibased solder) or Ag-based solder material (e.g., AgSn based solder). Inthe case of using the adhesive member, the optical member and themounting substrate are bonded so that contact surfaces of the mountingsubstrate or the metal layer and the optical member are bonded via theadhesive member, after which these are kept under a predeterminedtemperature and pressure. For example, thermocompression bonding can beused for such bonding. From the viewpoint of heat dissipation, theadhesive member is preferably disposed over the entire surface betweenthe mounting board or metal layer and the optical member. Also, anadhesive agent such as a UV-setting adhesive agent, a thermosettingadhesive agent may be used.

Mounting Board 1

The mounting board 1 is used to mount the semiconductor laser element 4,the optical member 5, and other components that constitute thesemiconductor laser device. The mounting board 1 is utilized also toallow heat generated in the semiconductor laser element 4 to beefficiently released to the outside. The mounting board 1 is typicallymade of an electrically insulating ceramics such as AlN, SiC, oraluminium oxide. In view of heat dissipation, another metal member (suchas copper or aluminum), another insulating ceramics made of anothermaterial, or the like may be further disposed on the lower surface ofthe insulating ceramics.

The thickness of the mounting board 1 can be appropriately selected, andan example thereof is about 0.2 to 5 mm.

There are no particular restrictions on the size and shape of themounting board 1, which can be suitably adjusted according to the size,shape, and so forth of the semiconductor laser device to be obtained.Examples of the planar shape include polygons such as rectangle, circle,ellipse, or the like. The mounting board 1 may have irregularities orthe like on the surface thereof, but the surface is preferably flat. Anexample of the mounting board 1 is a plate-like, rectangular mountingboard 1 with a side of about 2 to 30 mm.

The mounting board 1 may include a wiring pattern on a front surfacethereof. Also, the mounting board 1 may include terminals for connectingto an external power supply. The wiring pattern or the like may beembedded inside the mounting board 1. With the arrangement of theterminals on the front surface of the mounting board for connecting toan external power source, the entire back surface of the mounting board1 can serve as a heat dissipation surface.

Submount 3

A submount 3 may be arranged on the mounting board 1. In this case, thesemiconductor laser element 4 is arranged on the submount 3. Thesubmount 3 is made of a material with good thermal conductivity to aidin the heat dissipation of the semiconductor laser element 4, and ispreferably made of a material having thermal conductivity higher thanthat of silicon. Examples of such material include AlN, CuW, diamond,SiC and ceramics. Among these, the submount is preferably made ofmonocrystalline AlN or SiC.

The submount 3 may have an appropriate thickness, and an example thereofis in a range of about 100 to 500 μm, preferably about 120 to 400 μm andmore preferably about 150 to 300 μm. With a thickness of the submount 3greater than a certain value, light from the semiconductor laser elementcan be efficiently reflected by the reflecting member and extracted. Thesubmount 3 may have a thickness such that the light emission point ofthe semiconductor laser element to be located upper side than the lowerend of the reflective film. The height of the semiconductor laserelement is preferably selected so that a desired portion of the lightemitted from the semiconductor laser element (more specifically, aportion of light having light intensity to be reflected) is to beincident on the reflective film.

The submount 3 may have any appropriate planar shape, and examplesthereof include polygons such as rectangle, circle, ellipse, and shapessimilar to these. The size of the submount 3 can be appropriatelyadjusted according to the heat dissipation and the characteristics ofthe semiconductor laser device to be obtained. For example, the submount3 has an area greater than an area of the surface of the semiconductorlaser element 4 in plan view. That is, in plan view, the submount 3 hasa length and width greater than the length and width of thesemiconductor laser element 4, respectively. With this arrangement, allor substantially all of the semiconductor laser element 4 can bedisposed on the submount 3, which allows for ensuring a heat dissipationpath.

One submount 3 or a plurality of submounts 3 may be disposed on themounting board 1. In the case of disposing a plurality of submounts 3,they are preferably disposed in a matrix, for example.

The submount 3 is usually disposed on the mounting board 1 via theabove-described metal layer and/or adhesive member. The metal layer maybe disposed in a planar area that is less than the planar area of thesubmount 3, or may be disposed in a planar area equal to the planar areaof the submount 3. Also, it may be disposed extending out from the edgesof the submount 3.

Semiconductor Laser Element 4

In the semiconductor laser element 4, when voltage is applied andcurrent flows at or above a threshold value, laser oscillation occurs atthe active layer and a region surrounding the active layer, and thegenerated laser light is emitted through a waveguide region to theoutside. This semiconductor laser element 4 can be any known laserelement having a structure in which a plurality of semiconductor layersare layered. For instance, examples of the semiconductor laser element 4include an element having a structure in which an n-type semiconductorlayer, an active layer, and a p-type semiconductor layer are layered inthat order over a conductive substrate, and an insulating film,electrodes, and the like are formed on a surface of the semiconductorlayer. Examples of the material of the semiconductor layer include agroup III-V compound, and a nitride semiconductor is particularlypreferable.

The semiconductor laser element 4 is arranged on the submount 3. Withthis arrangement, heat generated from the semiconductor laser element 4can be efficiently escaped through the submount 3 or the like to themounting board 1. The semiconductor laser element 4 may be junction-upmounted (i.e., face-up mounted), in which the substrate side is themounting surface, but is preferably junction-down mounted (i.e.,face-down mounted). With the junction-down mounting, a portion of thesemiconductor laser element 4 in which the oscillation occurs can beclose to the submount 3 and the mounting board 1 below. Such arrangementof the portion of laser light oscillation, in which heat can easily begenerated, to be close to the submount 3 and the mounting board 1 allowsfor more effective heat dissipation. In the case of junction-downmounting, the semiconductor laser element 4 is preferably disposed sothat a portion of the semiconductor laser element 4 protrudes to theoptical member 5 side beyond the end of the submount 3. The protrudinglength can be about 10 to 20 μm, for example. This can reduce reflectionof the laser light by the submount, and can also shorten the distancebetween the semiconductor laser element 4 and the optical member 5 in adirection parallel to the surface of the mounting board. That is, thesemiconductor laser element 4 can be arranged close to the opticalmember 5 (discussed below). With this arrangement, the semiconductorlaser device can be smaller in size. Also, generally, heat is generatedat a semiconductor layer side of the semiconductor laser element 4, sothat heat dissipation can be better improved by junction-down mounting,in which the semiconductor layer side can serve as the mounting boardside, that is, the portion where heat is generated can be located closeto the submount 3 or the mounting board 1.

One semiconductor laser element 4 or a plurality of semiconductor laserelements 4 may be disposed on one submount 3. The plurality ofsemiconductor laser elements 4 may all have the same wavelength band, ormay have different wavelength bands. Also, the plurality ofsemiconductor laser elements 4 may be disposed in a matrix.

Cap

A semiconductor laser device 10 further includes a cap 8 attached to themounting board 1 so as to cover the semiconductor laser element 4 andthe optical member 5, and this cap is preferably sealed, and morepreferably is sealed airtight. In particular, in the case of using asemiconductor laser element 4 in which a semiconductor material with anoscillation wavelength of about 300 to 600 nm (such as a nitridesemiconductor) is used, organic material, moisture, or the like caneasily be collected. For this reason, arrangement of the cap 8 canincrease airtightness inside the laser device and can increasewaterproof performance and dustproof performance. Also, in this case,members disposed in the interior of the laser device that is sealedairtight by the cap 8 are preferably members that do not contain anyresin or other organic matter.

Examples of the shape of the cap 8 include a bottomed cylinder (acircular cylinder, polygonal cylinder, etc.), a truncated cone (acircular truncated cone, a polygonal truncated pyramid, etc.), a dome,and modifications of these shapes. The cap 8 can be made of a materialsuch as nickel, cobalt, iron, a Ni—Fe alloy, Kovar, brass, or the like.The cap 8 arranged on the mounting board 1 preferably has an Is openingin one surface thereof. It is preferable that a light-transmissivemember 7 arranged in the opening. Laser light can be extracted from thelight-transmissive member 7. The cap 8 can be fixed to the mountingboard 1 by a known method such as resistance welding, soldering, oranother known method.

Lens

A lens serves to diffuse, converge, or turn the laser light intoparallel light. The lens may be disposed in the emission direction ofthe laser light reflected by the optical member mirror, or the lens maybe disposed on a portion to which laser light from the semiconductorlaser element is irradiated, which is between the semiconductor laserelement and the optical member.

The lens is made of a material that can transmit laser light, and can bemade of any material that is typically used, such as glass, quartz,synthetic quartz, sapphire, transparent ceramics, and plastics. Toaccommodate various kinds of application, it is preferable for the lightextracted from the semiconductor laser device to be turned into parallellight, and for this purpose, it is preferable to use a collimating lensso that the laser light will be emitted from the semiconductor laserdevice in the form of parallel light. The lens may have any appropriateshape, but the shape of the lens is preferably circular or elliptical.The size of the lens can be determined appropriately according to thelaser light that is to be extracted from the semiconductor laser device.

Embodiment 3: Method for Manufacturing Semiconductor Laser Device

The method for manufacturing a semiconductor laser device in thisembodiment includes;

fixing the above-described optical member and semiconductor laserelement to a mounting board so that laser light emitted from thesemiconductor laser element can be irradiated to the reflective film ofthe optical member.

The semiconductor laser element may first be fixed to the mountingboard, and then the optical member fixed to the mounting board so thatlaser light emitted from the semiconductor laser element to strikes thereflective film of the optical member, or the optical member may firstbe fixed to the mounting board, and then the semiconductor laser elementfixed to the mounting board so that laser light strikes the reflectivefilm of the optical member, or both may be fixed to the mounting boardat the same time.

Fixing the semiconductor laser element and the optical member in thesemanners allows laser light emitted from the semiconductor laser elementto be reflected in a direction that is different from the emissiondirection.

In the case where the optical member is fixed to the mounting board, thesurface of the optical member to face the mounting board is preferablyfixed to the mounting board so as to be at a 45-degree angle withrespect a surface of the mounting board surface. Accordingly, thesurface of the optical member that to face the mounting board ispreferably either the {110} plane or the {100} plane of the siliconsubstrate, and it is more preferable that the surface is the {100}plane. With this arrangement, the {110} plane, which has not undergonethe above-described etching, can serve as the reflecting surface. Suchthe {110} plane has no surface roughness or flaws caused by etching,which is more suitable to serve as the reflecting surface. In the casewhere the {110} plane is fixed to the mounting board, the {100} planecan be the reflecting surface that is inclined at a 45-degree angle withrespect to the surface of the mounting board, and in the case where the{100} plane is fixed to the mounting board, the {110} plane can be thereflecting surface that is inclined at a 45-degree angle with respect tothe surface of the mounting board.

In the case where the optical member is fixed to the mounting board, theoptical member is preferably fixed via a metal layer and/or an adhesivemember, as described above.

In the case where the semiconductor laser element is fixed to themounting board, it is preferable that the semiconductor laser element isfixed to the submount and the submount is then fixed to the mountingboard via the metal layer and/or the adhesive member, or that thesubmount is fixed to the mounting board, and the semiconductor laserelement is fixed to this submount. In this case, in the case where thesemiconductor laser element is junction-down mounted, as describedabove, the semiconductor laser element is preferably disposed so that aportion of the semiconductor laser element preferably protrudes from anend of the submount toward the optical member. The semiconductor laserto element, the submount, and the mounting board can be fixed via theabove-mentioned metal layer and/or adhesive member.

The optical member is fixed to the mounting board, thereafter, thesemiconductor laser element is fixed to the mounting board, which allowsfor image-recognizing the position of the optical member using a cameraor the like, and determining a position on which the semiconductor laserelement is mounted based on the position of the optical member as areference. Consequently, the semiconductor laser element and the opticalmember can be mounted at the accurate location by a simple method.

After fixing the semiconductor laser element and the optical member tothe mounting board, these members are electrically connected by diebonding, wire bonding, or the like.

In the case of mounting a lens, positioning and bonding of the lens maybe appropriately performed. After determining the portion on which thelens is to be mounted, the lens is fixed at an appropriate portion usingan epoxy resin, acrylic resin, or other such UV-curing adhesive, athermosetting adhesive, or the like.

In the case where the semiconductor laser device is sealed with a cap,the cap may optionally be bonded to the mounting board by resistancewelding, soldering, or the like. This sealing can be performed in dryair, a nitrogen atmosphere, or the like at a dew point of −10 ° C. orlower. It is preferable to perform a pretreatment involving ashing, heattreatment, or another such method to remove any moisture or organicmaterial adhered to the members.

Examples of the method for manufacturing an optical member, the methodfor manufacturing a semiconductor laser device, and the semiconductorlaser device of the present invention is described below in detailthrough reference to the drawings.

EXAMPLE 1 Method for Manufacturing Optical Member

a: Provision of Silicon Substrate

First, a silicon substrate 11 is provided as shown in FIGS. 1A and 1B.This silicon substrate 11 has the {110} plane as its first main surface11 a and its second main surface 11 c. The thickness of the siliconsubstrate 11 is 500 μm, for example.

b: Formation of Mask Pattern

An SiO₂ film was formed using a CVD device over substantially the entiresurface of the first main surface 11 a of the silicon substrate 11.Then, using photolithography method, a mask-formation pattern havingopenings running along the <100> direction and the <110> direction isformed, and the SiO₂ film is wet-etched using buffered hydrofluoricacid. In this manner, a mask pattern 12 having openings 12 a and 12 brunning along the <100> direction and the <110> direction was formed.That is, the mask pattern 12 is made of SiO₂. In the mask pattern 12,the opening 12 had the width Q of 600 μm, and the width Z of 300 μm.Also the length X of the mask pattern along the side in the <100>direction was 500 μm, and the length Y of the side in the <110>direction was 700 μm.

c: Formation of Sloped Surfaces

Next, as shown in FIG. 2A, using the mask pattern 12 as a mask, thefirst main surface 11 a (the {110} plane) of the silicon substrate 11was wet-etched for 240 minutes with TMAH at a temperature ofapproximately 90° C. With this, along the <100> direction, 45-degreesloped surfaces with a depth of approximately 400 μm was exposed fromthe first main surface 11 a. The surfaces facing these 45-degree slopedsurfaces were also 45-degree sloped surfaces, which formed grooves thatwere substantially V-shaped in cross section. These 45-degree slopedsurfaces 11 b were the {100} plane.

At the same time, along the <110> direction, 35-degree sloped surfaceswith a depth of approximately 300 μm were exposed from the first mainsurface 11 a. The surfaces facing these 35-degree sloped surfaces werealso 35-degree sloped surfaces, which formed grooves that weresubstantially V-shaped in cross section.

After this, the mask pattern 12 was removed with buffered hydrofluoricacid as shown in FIG. 2B.

d: Formation of Reflective Film

As shown in FIG. 2C, an aluminum film of 200 nm was formed onthus-obtained the {100} plane of the silicon substrate 11, which was thesloped surfaces 11 b, using a sputtering device, so that reflectivefilms 13 were formed. These reflective films 13 each had a reflectivityof approximately 92%. In the present example, since surfaces on whichthe reflective films were to be formed were inclined at 45 degrees, itwas difficult to control thickness of the reflective films to be formed.Accordingly, a metal film whose thickness can be easily controlled evenin the case of being formed on a sloped surface was formed as thereflective film.

e: Division of Silicon Substrate

Next, as shown in FIG. 2D, the silicon substrate 11 was divided alongthe center of the etched V-shaped grooves (i.e., the portion at the apexof the V shape) extending in the <100> direction and the <110> directionof the silicon substrate 11.

With this division, an optical member can be obtained from a siliconsubstrate 11 having a substantially rectangular planar shape. As shownin FIGS. 8A to 8C, this optical member can have two different types ofsloped surfaces, that is, two 45-degree sloped surfaces (i.e., the {100}planes 11 b), and two 35-degree sloped surfaces (i.e., surfaces 11 d),and the two 45-degree sloped surfaces can serve as the reflectingsurfaces. The {100} planes 11 b and the 35-degree sloped surfaces 11 dare connected by, for example, surfaces each having a plurality ofplanar orientations with inclination angles that are graduallydifferent. They may also be connected by curved surfaces that arerounded.

As shown in FIG. 2E, optionally, auxiliary grooves 14 may be formed inthe { 110} plane of the silicon substrate, which is the second mainsurface 11 c, along the <100> direction of the silicon substrate 11 at aportion between V grooves, and the silicon substrate 11 may be dividedfrom the auxiliary grooves 14 in the <100> direction as shown in FIG.2F. In this manner, an optical member 5A in which just one slopedsurface of 45-degree serves as a reflecting surface.

EXAMPLE 2 Method for Manufacturing Optical Member

Similarly to Example 1, 45-degree sloped surfaces (surfaces 11 b inFIGS. 8A to 8C) and 35-degree sloped surfaces (surfaces 11 d in FIGS. 8Ato 8C) that define substantially V-shaped cross sections are formed inthe silicon substrate 11.

d′: Formation of Reflective Film

As shown in FIG. 3A, a layered structure having seven pairs of SiO₂film/ZrO₂ film (75 nm/50 nm) (for a total film thickness of 875 nm) isformed using an ECR device on the obtained {110} plane of the siliconsubstrate 11, which is the second main surface 11 c, to form areflective film 23. The reflectivity of this reflective film 23 isapproximately 99%.

After this, similarly to Example 1, the silicon substrate is divided asshown in FIG. 3B to form an optical member 15 in which two 45-degreesloped surfaces serve as reflecting surfaces.

EXAMPLE 3 Semiconductor Laser Device

As shown in FIGS. 4A and 4B, a semiconductor laser device 10 in thisExample mainly includes a mounting board 1, a submount 3 arranged on themounting board 1, a semiconductor laser element 4 arranged on thesubmount 3, and an optical member 5A. The semiconductor laser element 4and the optical member 5A are sealed airtight by the cap 8.

The mounting board 1 includes a rectangular insulating ceramic plate 1 amade of AlN and a metal member 1 b made of copper that is disposed on alower surface of the ceramic plate 1 a.

On a top surface of the mounting board 1, metal layers 2A and 2B aredisposed at portions on which the semiconductor laser element 4 and theoptical member 5A are mounted, respectively, so as to be apart from eachother.

The metal layer 2A has such a structure that titanium (having thicknessof 0.06 μm) and platinum (having thickness of 0.2 μm) layered in thatorder from the mounting board 1 side, over which is disposed anAu-Sn-based eutectic solder (having thickness of 3 μm). The metal layer2B has such a structure that titanium (having thickness of 0.06 μm),platinum (having thickness of 0.2 μm), gold (having thickness of 1 μm),and palladium (having thickness of 0.3 μm) laminated in that order fromthe mounting board 1 side, over which is disposed an Au-Sn-basedeutectic solder (having thickness of 3 μm).

The optical member 5A is made of silicon, and has the {110} plane, whichis the second main surface 11 c fixed to the mounting board 1, and the{100} plane, which is the sloped surface 11 b that is inclined 45degrees with respect to the second main surface 11 c. TA reflective film13 made of aluminum is formed on the sloped surface 11 b. The heightfrom a bottom surface to a top surface of the optical member 5A is 500μm. The height of the sloped surface 11 b is 200 μm.

The second main surface 11 c of the optical member 5A is fixed to themounting board 1 via the metal layer 2B. A distance between the opticalmember 5A and the submount 3 (described below) is, for example, 35 μm onthe front surface of the mounting board 1.

The submount 3 is made of AlN, and on the rear surface of the submount,titanium (having thickness of 0.06 μm) and platinum (having thickness of0.2 μm) are layered. The submount 3 has a rectangular-parallelepipedshape of 450×1900×200 (thickness) μm.

At the time of mounting the submount 3 on the mounting board 1, titanium(having thickness of 0.06 μm) and platinum (having thickness of 0.2 μm),Au-Sn-based eutectic solder (having thickness of 3 μm), and thenplatinum (0.2 μm) and titanium (0.06 μm) are layered in that order froma mounting board 1 side, and heating is performed.

The semiconductor laser element 4 is disposed on the submount 3 via anAu-Sn-based eutectic solder, for example. The semiconductor laserelement 4 is a substantially rectangular element (150×1200 μm) formed ofa nitride semiconductor and having an oscillation wavelength of 445 nm.

An end surface of the semiconductor laser element 4 on the opticalmember 5A side is disposed so as to protrude from an end surface of thesubmount 3 toward the optical member 5A. The distance between these endsurfaces is 15 μm, for example.

The light emission surface of the semiconductor laser element 4 facesthe reflecting surface of the optical member 5A, and is disposed about100 μm away from the optical member 5A.

The cap 8 is fixed on the mounting board 1 so that the semiconductorlaser element 4 and the optical member 5A is sealed airtight. The cap 8has an opening in its top surface, and a light-transmissive member 7made of glass is provided to the opening.

In this semiconductor laser device 10, a reflecting surface with goodsmoothness whose angular precision is easily achieved can be utilized,and a reflective film of good film quality is disposed on thisreflecting surface, which allows for obtaining a semiconductor laserdevice with good reflection efficiency and durability at a low cost.

Also, in this structure, most portion of the semiconductor laser element4 can be arranged on the submount 3, so that good heat dissipation bythe submount 3 can be ensured. Furthermore, in this structure, thesemiconductor laser element 4 and the optical member 5A can be arrangedclose to each other, a laser beam diameter of laser light can bemaintained to be small, so that light of high luminance can be obtained.

EXAMPLE 4 Semiconductor Laser Device

As shown in FIG. 5, a semiconductor laser device 20 in this Example isconfigured substantially the same as the semiconductor laser device 10,except that the semiconductor laser device 20 includes an optical member5 and two semiconductor laser elements 4 interposing the optical member5. A cap 28 includes a light-transmissive member 27 in an opening 8 a ofa metal member, and laser light can be extracted from thelight-transmissive member 27.

For the optical member 5 in Example 4, the optical member illustrated inFIG. 2D in the manufacture of the above-mentioned optical member can beused. The optical member 5 has a shape such that a tetragonal truncatedpyramid is arranged on a rectangular parallelepiped shape, and hassubstantially tetragonal top and bottom surfaces of mutually differentsizes. Further, between the top surface and the bottom surface, theoptical member 5 has two sloped surfaces 11 b inclined at 45 degrees tothe top surface and two non-sloped surfaces adjacent to the top surface.The optical member 5 has a height of 500 μm from the bottom surface tothe top surface. The height of the sloped surface 11 b is 200 μm.

The two semiconductor laser elements 4 are disposed facing the tworeflecting surfaces of the optical member 5.

EXAMPLE 5 Semiconductor Laser Device

As shown in FIG. 6, a semiconductor laser device 30 in this Example hassubstantially the same configuration as the semiconductor laser device10, except that the orientation of the optical member 15 disposed on themounting board 1 is different. A cap 38 includes a light-transmissivemember 37 provided to an opening in a metal member, and laser light canbe extracted through the light-transmissive member 37.

For the optical member 15 in Example 5, the optical member illustratedin FIG. 3B in the method for manufacturing the above-described opticalmember can be used. The reflecting surface of the optical member 15 isthe {110} plane of the silicon substrate, which is the second mainsurface 11 c, and a reflective film 23 made of a layered film of an SiO₂film (having thickness of 75 nm) and a ZrO₂ film (having thickness of 50nm) is arranged on reflecting surface. The {100} plane of the opticalmember 15, which is the sloped surface 11 b, is fixed to the mountingboard 1 via a metal layer 2B so that the reflecting surface has an angleof 45 degrees with respect to the mounting board 1 surface.

The optical member 15 has a height of 1000 μm from the lowermost end tothe uppermost end thereof.

EXAMPLE 6 Semiconductor Laser Device

As shown in FIG. 7, a semiconductor laser device 10B in this Example isconfigured substantially the same as the semiconductor laser device 10,except that a lens 6 is disposed between an optical member 5A and asemiconductor laser element 4. The lens 6 has a function of acollimating lens for converting the light emitted from the semiconductorlaser element 4 into coherent light.

According to the manufacturing method of the present disclosure, anoptical member having an inclined reflecting surface that is inexpensiveand has high-quality can be easily provided for a wide range ofsurface-mount laser packages of various sizes and shapes such as a highpower semiconductor laser package and low-cost compact laser package,which demand has been increased in recent years. Further, thesemiconductor laser device of the present disclosure can be widely usedin devices such as optical disks, optical communication systems,projectors, display, printers or meters.

What is claimed is:
 1. A method for manufacturing an optical memberadapted to be irradiated by laser light, the method comprising:providing a silicon substrate having a first main surface of a {110}plane; forming a mask pattern having an opening extending in a <100>direction on the first main surface of the silicon substrate; forming asloped surface of {100} plane in the silicon substrate by wet-etchingthe silicon substrate from a first main surface side using the maskpattern as a mask; and forming a reflective film on a second mainsurface of the silicon substrate, which is parallel to the first mainsurface, the reflective film being configured to reflect substantiallyall the laser light irradiated thereon.
 2. The method for manufacturingan optical member according to claim 1, wherein the forming of thereflective film on the second main surface of the silicon substrate isperformed after the forming of the sloped surface.
 3. The method formanufacturing an optical member according to claim 1, further comprisingdividing the silicon substrate from a lower end of the sloped surface inthe <100> direction, after the forming of the sloped surface.
 4. Themethod for manufacturing an optical member according to claim 3, whereinthe forming of the mask pattern includes forming the mask pattern havingan opening extending in a <110> direction in addition to the openingextending in the <100> direction.
 5. The method for manufacturing anoptical member according to claim 4, further comprising dividing thesilicon substrate in the <110> direction, after the forming of thesloped surface.
 6. A method for manufacturing a semiconductor laserdevice, comprising: manufacturing an optical member by the methodaccording to claim 1; and fixing the optical member and a semiconductorlaser element on a mounting board so that laser light emitted from thesemiconductor laser element is irradiated to the reflective film of theoptical member.
 7. The method for manufacturing a semiconductor laserdevice according to claim 6, wherein the fixing of the optical memberincludes fixing the optical member on the mounting board so that anangle defined by a main surface of the mounting board and a surface ofthe optical member on which the reflective film is formed is 45 degrees.8. The method for manufacturing a semiconductor laser device accordingto claim 6, wherein the fixing of the semiconductor laser elementincludes fixing the semiconductor element on the mounting board via asubmount.
 9. The method for manufacturing a semiconductor laser deviceaccording to claim 8, wherein the fixing of the semiconductor laserelement includes arranging the semiconductor laser element so that aportion of the semiconductor laser element protrudes from an end of thesubmount toward the optical member.
 10. The method for manufacturing asemiconductor laser device according to claim 6, further comprisingarranging a cap on the mounting board so as to hermetically seal thesemiconductor laser element and the optical member.
 11. The method formanufacturing a semiconductor laser device according to claim 8, whereinthe semiconductor laser clement is junction-down mounted on thesubmount.
 12. The method for manufacturing an optical member accordingto claim 1, wherein the forming of the sloped surface includes forming apair of sloped surfaces facing each other to define a groove having asubstantially V-shape in cross section.
 13. The method formanufacturing, an optical member according to claim 12, wherein theforming of the pair of sloped surfaces includes forming each of thesloped surfaces to form an angle of 135 degrees with respect to thefirst main surface of the silicon substrate.
 14. The method formanufacturing an optical member according to claim 3, wherein theforming of the sloped surfaces includes forming a plurality of pairs ofsloped surfaces facing each other so that each of the pair of slopedsurfaces defines a groove having a substantially V-shape in crosssection, the dividing of the silicon substrate includes dividing thesilicon substrate from the lower end of the groove defined by each ofthe pairs of sloped surfaces so that the sloped surfaces arerespectively arranged on both sides of the optical member after thedividing.
 15. The method for manufacturing an optical member accordingto claim 1, wherein the forming of the sloped surface includeswet-etching the silicon substrate by using tetramethylammonium hydroxideas an etchant.